1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * ROUTE - implementation of the IP router. 7 * 8 * Authors: Ross Biro 9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 10 * Alan Cox, <gw4pts@gw4pts.ampr.org> 11 * Linus Torvalds, <Linus.Torvalds@helsinki.fi> 12 * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 13 * 14 * Fixes: 15 * Alan Cox : Verify area fixes. 16 * Alan Cox : cli() protects routing changes 17 * Rui Oliveira : ICMP routing table updates 18 * (rco@di.uminho.pt) Routing table insertion and update 19 * Linus Torvalds : Rewrote bits to be sensible 20 * Alan Cox : Added BSD route gw semantics 21 * Alan Cox : Super /proc >4K 22 * Alan Cox : MTU in route table 23 * Alan Cox : MSS actually. Also added the window 24 * clamper. 25 * Sam Lantinga : Fixed route matching in rt_del() 26 * Alan Cox : Routing cache support. 27 * Alan Cox : Removed compatibility cruft. 28 * Alan Cox : RTF_REJECT support. 29 * Alan Cox : TCP irtt support. 30 * Jonathan Naylor : Added Metric support. 31 * Miquel van Smoorenburg : BSD API fixes. 32 * Miquel van Smoorenburg : Metrics. 33 * Alan Cox : Use __u32 properly 34 * Alan Cox : Aligned routing errors more closely with BSD 35 * our system is still very different. 36 * Alan Cox : Faster /proc handling 37 * Alexey Kuznetsov : Massive rework to support tree based routing, 38 * routing caches and better behaviour. 39 * 40 * Olaf Erb : irtt wasn't being copied right. 41 * Bjorn Ekwall : Kerneld route support. 42 * Alan Cox : Multicast fixed (I hope) 43 * Pavel Krauz : Limited broadcast fixed 44 * Mike McLagan : Routing by source 45 * Alexey Kuznetsov : End of old history. Split to fib.c and 46 * route.c and rewritten from scratch. 47 * Andi Kleen : Load-limit warning messages. 48 * Vitaly E. Lavrov : Transparent proxy revived after year coma. 49 * Vitaly E. Lavrov : Race condition in ip_route_input_slow. 50 * Tobias Ringstrom : Uninitialized res.type in ip_route_output_slow. 51 * Vladimir V. Ivanov : IP rule info (flowid) is really useful. 52 * Marc Boucher : routing by fwmark 53 * Robert Olsson : Added rt_cache statistics 54 * Arnaldo C. Melo : Convert proc stuff to seq_file 55 * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes. 56 * Ilia Sotnikov : Ignore TOS on PMTUD and Redirect 57 * Ilia Sotnikov : Removed TOS from hash calculations 58 * 59 * This program is free software; you can redistribute it and/or 60 * modify it under the terms of the GNU General Public License 61 * as published by the Free Software Foundation; either version 62 * 2 of the License, or (at your option) any later version. 63 */ 64 65 #define pr_fmt(fmt) "IPv4: " fmt 66 67 #include <linux/module.h> 68 #include <asm/uaccess.h> 69 #include <linux/bitops.h> 70 #include <linux/types.h> 71 #include <linux/kernel.h> 72 #include <linux/mm.h> 73 #include <linux/string.h> 74 #include <linux/socket.h> 75 #include <linux/sockios.h> 76 #include <linux/errno.h> 77 #include <linux/in.h> 78 #include <linux/inet.h> 79 #include <linux/netdevice.h> 80 #include <linux/proc_fs.h> 81 #include <linux/init.h> 82 #include <linux/skbuff.h> 83 #include <linux/inetdevice.h> 84 #include <linux/igmp.h> 85 #include <linux/pkt_sched.h> 86 #include <linux/mroute.h> 87 #include <linux/netfilter_ipv4.h> 88 #include <linux/random.h> 89 #include <linux/rcupdate.h> 90 #include <linux/times.h> 91 #include <linux/slab.h> 92 #include <linux/jhash.h> 93 #include <net/dst.h> 94 #include <net/dst_metadata.h> 95 #include <net/net_namespace.h> 96 #include <net/protocol.h> 97 #include <net/ip.h> 98 #include <net/route.h> 99 #include <net/inetpeer.h> 100 #include <net/sock.h> 101 #include <net/ip_fib.h> 102 #include <net/arp.h> 103 #include <net/tcp.h> 104 #include <net/icmp.h> 105 #include <net/xfrm.h> 106 #include <net/lwtunnel.h> 107 #include <net/netevent.h> 108 #include <net/rtnetlink.h> 109 #ifdef CONFIG_SYSCTL 110 #include <linux/sysctl.h> 111 #include <linux/kmemleak.h> 112 #endif 113 #include <net/secure_seq.h> 114 #include <net/ip_tunnels.h> 115 #include <net/l3mdev.h> 116 117 #define RT_FL_TOS(oldflp4) \ 118 ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)) 119 120 #define RT_GC_TIMEOUT (300*HZ) 121 122 static int ip_rt_max_size; 123 static int ip_rt_redirect_number __read_mostly = 9; 124 static int ip_rt_redirect_load __read_mostly = HZ / 50; 125 static int ip_rt_redirect_silence __read_mostly = ((HZ / 50) << (9 + 1)); 126 static int ip_rt_error_cost __read_mostly = HZ; 127 static int ip_rt_error_burst __read_mostly = 5 * HZ; 128 static int ip_rt_mtu_expires __read_mostly = 10 * 60 * HZ; 129 static int ip_rt_min_pmtu __read_mostly = 512 + 20 + 20; 130 static int ip_rt_min_advmss __read_mostly = 256; 131 132 static int ip_rt_gc_timeout __read_mostly = RT_GC_TIMEOUT; 133 /* 134 * Interface to generic destination cache. 135 */ 136 137 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie); 138 static unsigned int ipv4_default_advmss(const struct dst_entry *dst); 139 static unsigned int ipv4_mtu(const struct dst_entry *dst); 140 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst); 141 static void ipv4_link_failure(struct sk_buff *skb); 142 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 143 struct sk_buff *skb, u32 mtu); 144 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, 145 struct sk_buff *skb); 146 static void ipv4_dst_destroy(struct dst_entry *dst); 147 148 static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old) 149 { 150 WARN_ON(1); 151 return NULL; 152 } 153 154 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 155 struct sk_buff *skb, 156 const void *daddr); 157 158 static struct dst_ops ipv4_dst_ops = { 159 .family = AF_INET, 160 .check = ipv4_dst_check, 161 .default_advmss = ipv4_default_advmss, 162 .mtu = ipv4_mtu, 163 .cow_metrics = ipv4_cow_metrics, 164 .destroy = ipv4_dst_destroy, 165 .negative_advice = ipv4_negative_advice, 166 .link_failure = ipv4_link_failure, 167 .update_pmtu = ip_rt_update_pmtu, 168 .redirect = ip_do_redirect, 169 .local_out = __ip_local_out, 170 .neigh_lookup = ipv4_neigh_lookup, 171 }; 172 173 #define ECN_OR_COST(class) TC_PRIO_##class 174 175 const __u8 ip_tos2prio[16] = { 176 TC_PRIO_BESTEFFORT, 177 ECN_OR_COST(BESTEFFORT), 178 TC_PRIO_BESTEFFORT, 179 ECN_OR_COST(BESTEFFORT), 180 TC_PRIO_BULK, 181 ECN_OR_COST(BULK), 182 TC_PRIO_BULK, 183 ECN_OR_COST(BULK), 184 TC_PRIO_INTERACTIVE, 185 ECN_OR_COST(INTERACTIVE), 186 TC_PRIO_INTERACTIVE, 187 ECN_OR_COST(INTERACTIVE), 188 TC_PRIO_INTERACTIVE_BULK, 189 ECN_OR_COST(INTERACTIVE_BULK), 190 TC_PRIO_INTERACTIVE_BULK, 191 ECN_OR_COST(INTERACTIVE_BULK) 192 }; 193 EXPORT_SYMBOL(ip_tos2prio); 194 195 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat); 196 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field) 197 198 #ifdef CONFIG_PROC_FS 199 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos) 200 { 201 if (*pos) 202 return NULL; 203 return SEQ_START_TOKEN; 204 } 205 206 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos) 207 { 208 ++*pos; 209 return NULL; 210 } 211 212 static void rt_cache_seq_stop(struct seq_file *seq, void *v) 213 { 214 } 215 216 static int rt_cache_seq_show(struct seq_file *seq, void *v) 217 { 218 if (v == SEQ_START_TOKEN) 219 seq_printf(seq, "%-127s\n", 220 "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\t" 221 "Metric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\t" 222 "HHUptod\tSpecDst"); 223 return 0; 224 } 225 226 static const struct seq_operations rt_cache_seq_ops = { 227 .start = rt_cache_seq_start, 228 .next = rt_cache_seq_next, 229 .stop = rt_cache_seq_stop, 230 .show = rt_cache_seq_show, 231 }; 232 233 static int rt_cache_seq_open(struct inode *inode, struct file *file) 234 { 235 return seq_open(file, &rt_cache_seq_ops); 236 } 237 238 static const struct file_operations rt_cache_seq_fops = { 239 .owner = THIS_MODULE, 240 .open = rt_cache_seq_open, 241 .read = seq_read, 242 .llseek = seq_lseek, 243 .release = seq_release, 244 }; 245 246 247 static void *rt_cpu_seq_start(struct seq_file *seq, loff_t *pos) 248 { 249 int cpu; 250 251 if (*pos == 0) 252 return SEQ_START_TOKEN; 253 254 for (cpu = *pos-1; cpu < nr_cpu_ids; ++cpu) { 255 if (!cpu_possible(cpu)) 256 continue; 257 *pos = cpu+1; 258 return &per_cpu(rt_cache_stat, cpu); 259 } 260 return NULL; 261 } 262 263 static void *rt_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos) 264 { 265 int cpu; 266 267 for (cpu = *pos; cpu < nr_cpu_ids; ++cpu) { 268 if (!cpu_possible(cpu)) 269 continue; 270 *pos = cpu+1; 271 return &per_cpu(rt_cache_stat, cpu); 272 } 273 return NULL; 274 275 } 276 277 static void rt_cpu_seq_stop(struct seq_file *seq, void *v) 278 { 279 280 } 281 282 static int rt_cpu_seq_show(struct seq_file *seq, void *v) 283 { 284 struct rt_cache_stat *st = v; 285 286 if (v == SEQ_START_TOKEN) { 287 seq_printf(seq, "entries in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src out_hit out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n"); 288 return 0; 289 } 290 291 seq_printf(seq,"%08x %08x %08x %08x %08x %08x %08x %08x " 292 " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n", 293 dst_entries_get_slow(&ipv4_dst_ops), 294 0, /* st->in_hit */ 295 st->in_slow_tot, 296 st->in_slow_mc, 297 st->in_no_route, 298 st->in_brd, 299 st->in_martian_dst, 300 st->in_martian_src, 301 302 0, /* st->out_hit */ 303 st->out_slow_tot, 304 st->out_slow_mc, 305 306 0, /* st->gc_total */ 307 0, /* st->gc_ignored */ 308 0, /* st->gc_goal_miss */ 309 0, /* st->gc_dst_overflow */ 310 0, /* st->in_hlist_search */ 311 0 /* st->out_hlist_search */ 312 ); 313 return 0; 314 } 315 316 static const struct seq_operations rt_cpu_seq_ops = { 317 .start = rt_cpu_seq_start, 318 .next = rt_cpu_seq_next, 319 .stop = rt_cpu_seq_stop, 320 .show = rt_cpu_seq_show, 321 }; 322 323 324 static int rt_cpu_seq_open(struct inode *inode, struct file *file) 325 { 326 return seq_open(file, &rt_cpu_seq_ops); 327 } 328 329 static const struct file_operations rt_cpu_seq_fops = { 330 .owner = THIS_MODULE, 331 .open = rt_cpu_seq_open, 332 .read = seq_read, 333 .llseek = seq_lseek, 334 .release = seq_release, 335 }; 336 337 #ifdef CONFIG_IP_ROUTE_CLASSID 338 static int rt_acct_proc_show(struct seq_file *m, void *v) 339 { 340 struct ip_rt_acct *dst, *src; 341 unsigned int i, j; 342 343 dst = kcalloc(256, sizeof(struct ip_rt_acct), GFP_KERNEL); 344 if (!dst) 345 return -ENOMEM; 346 347 for_each_possible_cpu(i) { 348 src = (struct ip_rt_acct *)per_cpu_ptr(ip_rt_acct, i); 349 for (j = 0; j < 256; j++) { 350 dst[j].o_bytes += src[j].o_bytes; 351 dst[j].o_packets += src[j].o_packets; 352 dst[j].i_bytes += src[j].i_bytes; 353 dst[j].i_packets += src[j].i_packets; 354 } 355 } 356 357 seq_write(m, dst, 256 * sizeof(struct ip_rt_acct)); 358 kfree(dst); 359 return 0; 360 } 361 362 static int rt_acct_proc_open(struct inode *inode, struct file *file) 363 { 364 return single_open(file, rt_acct_proc_show, NULL); 365 } 366 367 static const struct file_operations rt_acct_proc_fops = { 368 .owner = THIS_MODULE, 369 .open = rt_acct_proc_open, 370 .read = seq_read, 371 .llseek = seq_lseek, 372 .release = single_release, 373 }; 374 #endif 375 376 static int __net_init ip_rt_do_proc_init(struct net *net) 377 { 378 struct proc_dir_entry *pde; 379 380 pde = proc_create("rt_cache", S_IRUGO, net->proc_net, 381 &rt_cache_seq_fops); 382 if (!pde) 383 goto err1; 384 385 pde = proc_create("rt_cache", S_IRUGO, 386 net->proc_net_stat, &rt_cpu_seq_fops); 387 if (!pde) 388 goto err2; 389 390 #ifdef CONFIG_IP_ROUTE_CLASSID 391 pde = proc_create("rt_acct", 0, net->proc_net, &rt_acct_proc_fops); 392 if (!pde) 393 goto err3; 394 #endif 395 return 0; 396 397 #ifdef CONFIG_IP_ROUTE_CLASSID 398 err3: 399 remove_proc_entry("rt_cache", net->proc_net_stat); 400 #endif 401 err2: 402 remove_proc_entry("rt_cache", net->proc_net); 403 err1: 404 return -ENOMEM; 405 } 406 407 static void __net_exit ip_rt_do_proc_exit(struct net *net) 408 { 409 remove_proc_entry("rt_cache", net->proc_net_stat); 410 remove_proc_entry("rt_cache", net->proc_net); 411 #ifdef CONFIG_IP_ROUTE_CLASSID 412 remove_proc_entry("rt_acct", net->proc_net); 413 #endif 414 } 415 416 static struct pernet_operations ip_rt_proc_ops __net_initdata = { 417 .init = ip_rt_do_proc_init, 418 .exit = ip_rt_do_proc_exit, 419 }; 420 421 static int __init ip_rt_proc_init(void) 422 { 423 return register_pernet_subsys(&ip_rt_proc_ops); 424 } 425 426 #else 427 static inline int ip_rt_proc_init(void) 428 { 429 return 0; 430 } 431 #endif /* CONFIG_PROC_FS */ 432 433 static inline bool rt_is_expired(const struct rtable *rth) 434 { 435 return rth->rt_genid != rt_genid_ipv4(dev_net(rth->dst.dev)); 436 } 437 438 void rt_cache_flush(struct net *net) 439 { 440 rt_genid_bump_ipv4(net); 441 } 442 443 static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, 444 struct sk_buff *skb, 445 const void *daddr) 446 { 447 struct net_device *dev = dst->dev; 448 const __be32 *pkey = daddr; 449 const struct rtable *rt; 450 struct neighbour *n; 451 452 rt = (const struct rtable *) dst; 453 if (rt->rt_gateway) 454 pkey = (const __be32 *) &rt->rt_gateway; 455 else if (skb) 456 pkey = &ip_hdr(skb)->daddr; 457 458 n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey); 459 if (n) 460 return n; 461 return neigh_create(&arp_tbl, pkey, dev); 462 } 463 464 #define IP_IDENTS_SZ 2048u 465 466 static atomic_t *ip_idents __read_mostly; 467 static u32 *ip_tstamps __read_mostly; 468 469 /* In order to protect privacy, we add a perturbation to identifiers 470 * if one generator is seldom used. This makes hard for an attacker 471 * to infer how many packets were sent between two points in time. 472 */ 473 u32 ip_idents_reserve(u32 hash, int segs) 474 { 475 u32 *p_tstamp = ip_tstamps + hash % IP_IDENTS_SZ; 476 atomic_t *p_id = ip_idents + hash % IP_IDENTS_SZ; 477 u32 old = ACCESS_ONCE(*p_tstamp); 478 u32 now = (u32)jiffies; 479 u32 delta = 0; 480 481 if (old != now && cmpxchg(p_tstamp, old, now) == old) 482 delta = prandom_u32_max(now - old); 483 484 return atomic_add_return(segs + delta, p_id) - segs; 485 } 486 EXPORT_SYMBOL(ip_idents_reserve); 487 488 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) 489 { 490 static u32 ip_idents_hashrnd __read_mostly; 491 u32 hash, id; 492 493 net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd)); 494 495 hash = jhash_3words((__force u32)iph->daddr, 496 (__force u32)iph->saddr, 497 iph->protocol ^ net_hash_mix(net), 498 ip_idents_hashrnd); 499 id = ip_idents_reserve(hash, segs); 500 iph->id = htons(id); 501 } 502 EXPORT_SYMBOL(__ip_select_ident); 503 504 static void __build_flow_key(struct flowi4 *fl4, const struct sock *sk, 505 const struct iphdr *iph, 506 int oif, u8 tos, 507 u8 prot, u32 mark, int flow_flags) 508 { 509 if (sk) { 510 const struct inet_sock *inet = inet_sk(sk); 511 512 oif = sk->sk_bound_dev_if; 513 mark = sk->sk_mark; 514 tos = RT_CONN_FLAGS(sk); 515 prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol; 516 } 517 flowi4_init_output(fl4, oif, mark, tos, 518 RT_SCOPE_UNIVERSE, prot, 519 flow_flags, 520 iph->daddr, iph->saddr, 0, 0); 521 } 522 523 static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 524 const struct sock *sk) 525 { 526 const struct iphdr *iph = ip_hdr(skb); 527 int oif = skb->dev->ifindex; 528 u8 tos = RT_TOS(iph->tos); 529 u8 prot = iph->protocol; 530 u32 mark = skb->mark; 531 532 __build_flow_key(fl4, sk, iph, oif, tos, prot, mark, 0); 533 } 534 535 static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 536 { 537 const struct inet_sock *inet = inet_sk(sk); 538 const struct ip_options_rcu *inet_opt; 539 __be32 daddr = inet->inet_daddr; 540 541 rcu_read_lock(); 542 inet_opt = rcu_dereference(inet->inet_opt); 543 if (inet_opt && inet_opt->opt.srr) 544 daddr = inet_opt->opt.faddr; 545 flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark, 546 RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, 547 inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol, 548 inet_sk_flowi_flags(sk), 549 daddr, inet->inet_saddr, 0, 0); 550 rcu_read_unlock(); 551 } 552 553 static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, 554 const struct sk_buff *skb) 555 { 556 if (skb) 557 build_skb_flow_key(fl4, skb, sk); 558 else 559 build_sk_flow_key(fl4, sk); 560 } 561 562 static inline void rt_free(struct rtable *rt) 563 { 564 call_rcu(&rt->dst.rcu_head, dst_rcu_free); 565 } 566 567 static DEFINE_SPINLOCK(fnhe_lock); 568 569 static void fnhe_flush_routes(struct fib_nh_exception *fnhe) 570 { 571 struct rtable *rt; 572 573 rt = rcu_dereference(fnhe->fnhe_rth_input); 574 if (rt) { 575 RCU_INIT_POINTER(fnhe->fnhe_rth_input, NULL); 576 rt_free(rt); 577 } 578 rt = rcu_dereference(fnhe->fnhe_rth_output); 579 if (rt) { 580 RCU_INIT_POINTER(fnhe->fnhe_rth_output, NULL); 581 rt_free(rt); 582 } 583 } 584 585 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) 586 { 587 struct fib_nh_exception *fnhe, *oldest; 588 589 oldest = rcu_dereference(hash->chain); 590 for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe; 591 fnhe = rcu_dereference(fnhe->fnhe_next)) { 592 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) 593 oldest = fnhe; 594 } 595 fnhe_flush_routes(oldest); 596 return oldest; 597 } 598 599 static inline u32 fnhe_hashfun(__be32 daddr) 600 { 601 static u32 fnhe_hashrnd __read_mostly; 602 u32 hval; 603 604 net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd)); 605 hval = jhash_1word((__force u32) daddr, fnhe_hashrnd); 606 return hash_32(hval, FNHE_HASH_SHIFT); 607 } 608 609 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe) 610 { 611 rt->rt_pmtu = fnhe->fnhe_pmtu; 612 rt->dst.expires = fnhe->fnhe_expires; 613 614 if (fnhe->fnhe_gw) { 615 rt->rt_flags |= RTCF_REDIRECTED; 616 rt->rt_gateway = fnhe->fnhe_gw; 617 rt->rt_uses_gateway = 1; 618 } 619 } 620 621 static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw, 622 u32 pmtu, unsigned long expires) 623 { 624 struct fnhe_hash_bucket *hash; 625 struct fib_nh_exception *fnhe; 626 struct rtable *rt; 627 unsigned int i; 628 int depth; 629 u32 hval = fnhe_hashfun(daddr); 630 631 spin_lock_bh(&fnhe_lock); 632 633 hash = rcu_dereference(nh->nh_exceptions); 634 if (!hash) { 635 hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC); 636 if (!hash) 637 goto out_unlock; 638 rcu_assign_pointer(nh->nh_exceptions, hash); 639 } 640 641 hash += hval; 642 643 depth = 0; 644 for (fnhe = rcu_dereference(hash->chain); fnhe; 645 fnhe = rcu_dereference(fnhe->fnhe_next)) { 646 if (fnhe->fnhe_daddr == daddr) 647 break; 648 depth++; 649 } 650 651 if (fnhe) { 652 if (gw) 653 fnhe->fnhe_gw = gw; 654 if (pmtu) { 655 fnhe->fnhe_pmtu = pmtu; 656 fnhe->fnhe_expires = max(1UL, expires); 657 } 658 /* Update all cached dsts too */ 659 rt = rcu_dereference(fnhe->fnhe_rth_input); 660 if (rt) 661 fill_route_from_fnhe(rt, fnhe); 662 rt = rcu_dereference(fnhe->fnhe_rth_output); 663 if (rt) 664 fill_route_from_fnhe(rt, fnhe); 665 } else { 666 if (depth > FNHE_RECLAIM_DEPTH) 667 fnhe = fnhe_oldest(hash); 668 else { 669 fnhe = kzalloc(sizeof(*fnhe), GFP_ATOMIC); 670 if (!fnhe) 671 goto out_unlock; 672 673 fnhe->fnhe_next = hash->chain; 674 rcu_assign_pointer(hash->chain, fnhe); 675 } 676 fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev)); 677 fnhe->fnhe_daddr = daddr; 678 fnhe->fnhe_gw = gw; 679 fnhe->fnhe_pmtu = pmtu; 680 fnhe->fnhe_expires = expires; 681 682 /* Exception created; mark the cached routes for the nexthop 683 * stale, so anyone caching it rechecks if this exception 684 * applies to them. 685 */ 686 rt = rcu_dereference(nh->nh_rth_input); 687 if (rt) 688 rt->dst.obsolete = DST_OBSOLETE_KILL; 689 690 for_each_possible_cpu(i) { 691 struct rtable __rcu **prt; 692 prt = per_cpu_ptr(nh->nh_pcpu_rth_output, i); 693 rt = rcu_dereference(*prt); 694 if (rt) 695 rt->dst.obsolete = DST_OBSOLETE_KILL; 696 } 697 } 698 699 fnhe->fnhe_stamp = jiffies; 700 701 out_unlock: 702 spin_unlock_bh(&fnhe_lock); 703 } 704 705 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4, 706 bool kill_route) 707 { 708 __be32 new_gw = icmp_hdr(skb)->un.gateway; 709 __be32 old_gw = ip_hdr(skb)->saddr; 710 struct net_device *dev = skb->dev; 711 struct in_device *in_dev; 712 struct fib_result res; 713 struct neighbour *n; 714 struct net *net; 715 716 switch (icmp_hdr(skb)->code & 7) { 717 case ICMP_REDIR_NET: 718 case ICMP_REDIR_NETTOS: 719 case ICMP_REDIR_HOST: 720 case ICMP_REDIR_HOSTTOS: 721 break; 722 723 default: 724 return; 725 } 726 727 if (rt->rt_gateway != old_gw) 728 return; 729 730 in_dev = __in_dev_get_rcu(dev); 731 if (!in_dev) 732 return; 733 734 net = dev_net(dev); 735 if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) || 736 ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) || 737 ipv4_is_zeronet(new_gw)) 738 goto reject_redirect; 739 740 if (!IN_DEV_SHARED_MEDIA(in_dev)) { 741 if (!inet_addr_onlink(in_dev, new_gw, old_gw)) 742 goto reject_redirect; 743 if (IN_DEV_SEC_REDIRECTS(in_dev) && ip_fib_check_default(new_gw, dev)) 744 goto reject_redirect; 745 } else { 746 if (inet_addr_type(net, new_gw) != RTN_UNICAST) 747 goto reject_redirect; 748 } 749 750 n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw); 751 if (!IS_ERR(n)) { 752 if (!(n->nud_state & NUD_VALID)) { 753 neigh_event_send(n, NULL); 754 } else { 755 if (fib_lookup(net, fl4, &res, 0) == 0) { 756 struct fib_nh *nh = &FIB_RES_NH(res); 757 758 update_or_create_fnhe(nh, fl4->daddr, new_gw, 759 0, jiffies + ip_rt_gc_timeout); 760 } 761 if (kill_route) 762 rt->dst.obsolete = DST_OBSOLETE_KILL; 763 call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n); 764 } 765 neigh_release(n); 766 } 767 return; 768 769 reject_redirect: 770 #ifdef CONFIG_IP_ROUTE_VERBOSE 771 if (IN_DEV_LOG_MARTIANS(in_dev)) { 772 const struct iphdr *iph = (const struct iphdr *) skb->data; 773 __be32 daddr = iph->daddr; 774 __be32 saddr = iph->saddr; 775 776 net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n" 777 " Advised path = %pI4 -> %pI4\n", 778 &old_gw, dev->name, &new_gw, 779 &saddr, &daddr); 780 } 781 #endif 782 ; 783 } 784 785 static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buff *skb) 786 { 787 struct rtable *rt; 788 struct flowi4 fl4; 789 const struct iphdr *iph = (const struct iphdr *) skb->data; 790 int oif = skb->dev->ifindex; 791 u8 tos = RT_TOS(iph->tos); 792 u8 prot = iph->protocol; 793 u32 mark = skb->mark; 794 795 rt = (struct rtable *) dst; 796 797 __build_flow_key(&fl4, sk, iph, oif, tos, prot, mark, 0); 798 __ip_do_redirect(rt, skb, &fl4, true); 799 } 800 801 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst) 802 { 803 struct rtable *rt = (struct rtable *)dst; 804 struct dst_entry *ret = dst; 805 806 if (rt) { 807 if (dst->obsolete > 0) { 808 ip_rt_put(rt); 809 ret = NULL; 810 } else if ((rt->rt_flags & RTCF_REDIRECTED) || 811 rt->dst.expires) { 812 ip_rt_put(rt); 813 ret = NULL; 814 } 815 } 816 return ret; 817 } 818 819 /* 820 * Algorithm: 821 * 1. The first ip_rt_redirect_number redirects are sent 822 * with exponential backoff, then we stop sending them at all, 823 * assuming that the host ignores our redirects. 824 * 2. If we did not see packets requiring redirects 825 * during ip_rt_redirect_silence, we assume that the host 826 * forgot redirected route and start to send redirects again. 827 * 828 * This algorithm is much cheaper and more intelligent than dumb load limiting 829 * in icmp.c. 830 * 831 * NOTE. Do not forget to inhibit load limiting for redirects (redundant) 832 * and "frag. need" (breaks PMTU discovery) in icmp.c. 833 */ 834 835 void ip_rt_send_redirect(struct sk_buff *skb) 836 { 837 struct rtable *rt = skb_rtable(skb); 838 struct in_device *in_dev; 839 struct inet_peer *peer; 840 struct net *net; 841 int log_martians; 842 int vif; 843 844 rcu_read_lock(); 845 in_dev = __in_dev_get_rcu(rt->dst.dev); 846 if (!in_dev || !IN_DEV_TX_REDIRECTS(in_dev)) { 847 rcu_read_unlock(); 848 return; 849 } 850 log_martians = IN_DEV_LOG_MARTIANS(in_dev); 851 vif = l3mdev_master_ifindex_rcu(rt->dst.dev); 852 rcu_read_unlock(); 853 854 net = dev_net(rt->dst.dev); 855 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, vif, 1); 856 if (!peer) { 857 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, 858 rt_nexthop(rt, ip_hdr(skb)->daddr)); 859 return; 860 } 861 862 /* No redirected packets during ip_rt_redirect_silence; 863 * reset the algorithm. 864 */ 865 if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) 866 peer->rate_tokens = 0; 867 868 /* Too many ignored redirects; do not send anything 869 * set dst.rate_last to the last seen redirected packet. 870 */ 871 if (peer->rate_tokens >= ip_rt_redirect_number) { 872 peer->rate_last = jiffies; 873 goto out_put_peer; 874 } 875 876 /* Check for load limit; set rate_last to the latest sent 877 * redirect. 878 */ 879 if (peer->rate_tokens == 0 || 880 time_after(jiffies, 881 (peer->rate_last + 882 (ip_rt_redirect_load << peer->rate_tokens)))) { 883 __be32 gw = rt_nexthop(rt, ip_hdr(skb)->daddr); 884 885 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); 886 peer->rate_last = jiffies; 887 ++peer->rate_tokens; 888 #ifdef CONFIG_IP_ROUTE_VERBOSE 889 if (log_martians && 890 peer->rate_tokens == ip_rt_redirect_number) 891 net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n", 892 &ip_hdr(skb)->saddr, inet_iif(skb), 893 &ip_hdr(skb)->daddr, &gw); 894 #endif 895 } 896 out_put_peer: 897 inet_putpeer(peer); 898 } 899 900 static int ip_error(struct sk_buff *skb) 901 { 902 struct in_device *in_dev = __in_dev_get_rcu(skb->dev); 903 struct rtable *rt = skb_rtable(skb); 904 struct inet_peer *peer; 905 unsigned long now; 906 struct net *net; 907 bool send; 908 int code; 909 910 /* IP on this device is disabled. */ 911 if (!in_dev) 912 goto out; 913 914 net = dev_net(rt->dst.dev); 915 if (!IN_DEV_FORWARD(in_dev)) { 916 switch (rt->dst.error) { 917 case EHOSTUNREACH: 918 __IP_INC_STATS(net, IPSTATS_MIB_INADDRERRORS); 919 break; 920 921 case ENETUNREACH: 922 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 923 break; 924 } 925 goto out; 926 } 927 928 switch (rt->dst.error) { 929 case EINVAL: 930 default: 931 goto out; 932 case EHOSTUNREACH: 933 code = ICMP_HOST_UNREACH; 934 break; 935 case ENETUNREACH: 936 code = ICMP_NET_UNREACH; 937 __IP_INC_STATS(net, IPSTATS_MIB_INNOROUTES); 938 break; 939 case EACCES: 940 code = ICMP_PKT_FILTERED; 941 break; 942 } 943 944 peer = inet_getpeer_v4(net->ipv4.peers, ip_hdr(skb)->saddr, 945 l3mdev_master_ifindex(skb->dev), 1); 946 947 send = true; 948 if (peer) { 949 now = jiffies; 950 peer->rate_tokens += now - peer->rate_last; 951 if (peer->rate_tokens > ip_rt_error_burst) 952 peer->rate_tokens = ip_rt_error_burst; 953 peer->rate_last = now; 954 if (peer->rate_tokens >= ip_rt_error_cost) 955 peer->rate_tokens -= ip_rt_error_cost; 956 else 957 send = false; 958 inet_putpeer(peer); 959 } 960 if (send) 961 icmp_send(skb, ICMP_DEST_UNREACH, code, 0); 962 963 out: kfree_skb(skb); 964 return 0; 965 } 966 967 static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 968 { 969 struct dst_entry *dst = &rt->dst; 970 struct fib_result res; 971 972 if (dst_metric_locked(dst, RTAX_MTU)) 973 return; 974 975 if (ipv4_mtu(dst) < mtu) 976 return; 977 978 if (mtu < ip_rt_min_pmtu) 979 mtu = ip_rt_min_pmtu; 980 981 if (rt->rt_pmtu == mtu && 982 time_before(jiffies, dst->expires - ip_rt_mtu_expires / 2)) 983 return; 984 985 rcu_read_lock(); 986 if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) { 987 struct fib_nh *nh = &FIB_RES_NH(res); 988 989 update_or_create_fnhe(nh, fl4->daddr, 0, mtu, 990 jiffies + ip_rt_mtu_expires); 991 } 992 rcu_read_unlock(); 993 } 994 995 static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 996 struct sk_buff *skb, u32 mtu) 997 { 998 struct rtable *rt = (struct rtable *) dst; 999 struct flowi4 fl4; 1000 1001 ip_rt_build_flow_key(&fl4, sk, skb); 1002 __ip_rt_update_pmtu(rt, &fl4, mtu); 1003 } 1004 1005 void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 1006 int oif, u32 mark, u8 protocol, int flow_flags) 1007 { 1008 const struct iphdr *iph = (const struct iphdr *) skb->data; 1009 struct flowi4 fl4; 1010 struct rtable *rt; 1011 1012 if (!mark) 1013 mark = IP4_REPLY_MARK(net, skb->mark); 1014 1015 __build_flow_key(&fl4, NULL, iph, oif, 1016 RT_TOS(iph->tos), protocol, mark, flow_flags); 1017 rt = __ip_route_output_key(net, &fl4); 1018 if (!IS_ERR(rt)) { 1019 __ip_rt_update_pmtu(rt, &fl4, mtu); 1020 ip_rt_put(rt); 1021 } 1022 } 1023 EXPORT_SYMBOL_GPL(ipv4_update_pmtu); 1024 1025 static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1026 { 1027 const struct iphdr *iph = (const struct iphdr *) skb->data; 1028 struct flowi4 fl4; 1029 struct rtable *rt; 1030 1031 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0); 1032 1033 if (!fl4.flowi4_mark) 1034 fl4.flowi4_mark = IP4_REPLY_MARK(sock_net(sk), skb->mark); 1035 1036 rt = __ip_route_output_key(sock_net(sk), &fl4); 1037 if (!IS_ERR(rt)) { 1038 __ip_rt_update_pmtu(rt, &fl4, mtu); 1039 ip_rt_put(rt); 1040 } 1041 } 1042 1043 void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 1044 { 1045 const struct iphdr *iph = (const struct iphdr *) skb->data; 1046 struct flowi4 fl4; 1047 struct rtable *rt; 1048 struct dst_entry *odst = NULL; 1049 bool new = false; 1050 1051 bh_lock_sock(sk); 1052 1053 if (!ip_sk_accept_pmtu(sk)) 1054 goto out; 1055 1056 odst = sk_dst_get(sk); 1057 1058 if (sock_owned_by_user(sk) || !odst) { 1059 __ipv4_sk_update_pmtu(skb, sk, mtu); 1060 goto out; 1061 } 1062 1063 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0); 1064 1065 rt = (struct rtable *)odst; 1066 if (odst->obsolete && !odst->ops->check(odst, 0)) { 1067 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1068 if (IS_ERR(rt)) 1069 goto out; 1070 1071 new = true; 1072 } 1073 1074 __ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu); 1075 1076 if (!dst_check(&rt->dst, 0)) { 1077 if (new) 1078 dst_release(&rt->dst); 1079 1080 rt = ip_route_output_flow(sock_net(sk), &fl4, sk); 1081 if (IS_ERR(rt)) 1082 goto out; 1083 1084 new = true; 1085 } 1086 1087 if (new) 1088 sk_dst_set(sk, &rt->dst); 1089 1090 out: 1091 bh_unlock_sock(sk); 1092 dst_release(odst); 1093 } 1094 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu); 1095 1096 void ipv4_redirect(struct sk_buff *skb, struct net *net, 1097 int oif, u32 mark, u8 protocol, int flow_flags) 1098 { 1099 const struct iphdr *iph = (const struct iphdr *) skb->data; 1100 struct flowi4 fl4; 1101 struct rtable *rt; 1102 1103 __build_flow_key(&fl4, NULL, iph, oif, 1104 RT_TOS(iph->tos), protocol, mark, flow_flags); 1105 rt = __ip_route_output_key(net, &fl4); 1106 if (!IS_ERR(rt)) { 1107 __ip_do_redirect(rt, skb, &fl4, false); 1108 ip_rt_put(rt); 1109 } 1110 } 1111 EXPORT_SYMBOL_GPL(ipv4_redirect); 1112 1113 void ipv4_sk_redirect(struct sk_buff *skb, struct sock *sk) 1114 { 1115 const struct iphdr *iph = (const struct iphdr *) skb->data; 1116 struct flowi4 fl4; 1117 struct rtable *rt; 1118 1119 __build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0); 1120 rt = __ip_route_output_key(sock_net(sk), &fl4); 1121 if (!IS_ERR(rt)) { 1122 __ip_do_redirect(rt, skb, &fl4, false); 1123 ip_rt_put(rt); 1124 } 1125 } 1126 EXPORT_SYMBOL_GPL(ipv4_sk_redirect); 1127 1128 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) 1129 { 1130 struct rtable *rt = (struct rtable *) dst; 1131 1132 /* All IPV4 dsts are created with ->obsolete set to the value 1133 * DST_OBSOLETE_FORCE_CHK which forces validation calls down 1134 * into this function always. 1135 * 1136 * When a PMTU/redirect information update invalidates a route, 1137 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or 1138 * DST_OBSOLETE_DEAD by dst_free(). 1139 */ 1140 if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt)) 1141 return NULL; 1142 return dst; 1143 } 1144 1145 static void ipv4_link_failure(struct sk_buff *skb) 1146 { 1147 struct rtable *rt; 1148 1149 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0); 1150 1151 rt = skb_rtable(skb); 1152 if (rt) 1153 dst_set_expires(&rt->dst, 0); 1154 } 1155 1156 static int ip_rt_bug(struct net *net, struct sock *sk, struct sk_buff *skb) 1157 { 1158 pr_debug("%s: %pI4 -> %pI4, %s\n", 1159 __func__, &ip_hdr(skb)->saddr, &ip_hdr(skb)->daddr, 1160 skb->dev ? skb->dev->name : "?"); 1161 kfree_skb(skb); 1162 WARN_ON(1); 1163 return 0; 1164 } 1165 1166 /* 1167 We do not cache source address of outgoing interface, 1168 because it is used only by IP RR, TS and SRR options, 1169 so that it out of fast path. 1170 1171 BTW remember: "addr" is allowed to be not aligned 1172 in IP options! 1173 */ 1174 1175 void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) 1176 { 1177 __be32 src; 1178 1179 if (rt_is_output_route(rt)) 1180 src = ip_hdr(skb)->saddr; 1181 else { 1182 struct fib_result res; 1183 struct flowi4 fl4; 1184 struct iphdr *iph; 1185 1186 iph = ip_hdr(skb); 1187 1188 memset(&fl4, 0, sizeof(fl4)); 1189 fl4.daddr = iph->daddr; 1190 fl4.saddr = iph->saddr; 1191 fl4.flowi4_tos = RT_TOS(iph->tos); 1192 fl4.flowi4_oif = rt->dst.dev->ifindex; 1193 fl4.flowi4_iif = skb->dev->ifindex; 1194 fl4.flowi4_mark = skb->mark; 1195 1196 rcu_read_lock(); 1197 if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) 1198 src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res); 1199 else 1200 src = inet_select_addr(rt->dst.dev, 1201 rt_nexthop(rt, iph->daddr), 1202 RT_SCOPE_UNIVERSE); 1203 rcu_read_unlock(); 1204 } 1205 memcpy(addr, &src, 4); 1206 } 1207 1208 #ifdef CONFIG_IP_ROUTE_CLASSID 1209 static void set_class_tag(struct rtable *rt, u32 tag) 1210 { 1211 if (!(rt->dst.tclassid & 0xFFFF)) 1212 rt->dst.tclassid |= tag & 0xFFFF; 1213 if (!(rt->dst.tclassid & 0xFFFF0000)) 1214 rt->dst.tclassid |= tag & 0xFFFF0000; 1215 } 1216 #endif 1217 1218 static unsigned int ipv4_default_advmss(const struct dst_entry *dst) 1219 { 1220 unsigned int advmss = dst_metric_raw(dst, RTAX_ADVMSS); 1221 1222 if (advmss == 0) { 1223 advmss = max_t(unsigned int, dst->dev->mtu - 40, 1224 ip_rt_min_advmss); 1225 if (advmss > 65535 - 40) 1226 advmss = 65535 - 40; 1227 } 1228 return advmss; 1229 } 1230 1231 static unsigned int ipv4_mtu(const struct dst_entry *dst) 1232 { 1233 const struct rtable *rt = (const struct rtable *) dst; 1234 unsigned int mtu = rt->rt_pmtu; 1235 1236 if (!mtu || time_after_eq(jiffies, rt->dst.expires)) 1237 mtu = dst_metric_raw(dst, RTAX_MTU); 1238 1239 if (mtu) 1240 return mtu; 1241 1242 mtu = dst->dev->mtu; 1243 1244 if (unlikely(dst_metric_locked(dst, RTAX_MTU))) { 1245 if (rt->rt_uses_gateway && mtu > 576) 1246 mtu = 576; 1247 } 1248 1249 mtu = min_t(unsigned int, mtu, IP_MAX_MTU); 1250 1251 return mtu - lwtunnel_headroom(dst->lwtstate, mtu); 1252 } 1253 1254 static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr) 1255 { 1256 struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions); 1257 struct fib_nh_exception *fnhe; 1258 u32 hval; 1259 1260 if (!hash) 1261 return NULL; 1262 1263 hval = fnhe_hashfun(daddr); 1264 1265 for (fnhe = rcu_dereference(hash[hval].chain); fnhe; 1266 fnhe = rcu_dereference(fnhe->fnhe_next)) { 1267 if (fnhe->fnhe_daddr == daddr) 1268 return fnhe; 1269 } 1270 return NULL; 1271 } 1272 1273 static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, 1274 __be32 daddr) 1275 { 1276 bool ret = false; 1277 1278 spin_lock_bh(&fnhe_lock); 1279 1280 if (daddr == fnhe->fnhe_daddr) { 1281 struct rtable __rcu **porig; 1282 struct rtable *orig; 1283 int genid = fnhe_genid(dev_net(rt->dst.dev)); 1284 1285 if (rt_is_input_route(rt)) 1286 porig = &fnhe->fnhe_rth_input; 1287 else 1288 porig = &fnhe->fnhe_rth_output; 1289 orig = rcu_dereference(*porig); 1290 1291 if (fnhe->fnhe_genid != genid) { 1292 fnhe->fnhe_genid = genid; 1293 fnhe->fnhe_gw = 0; 1294 fnhe->fnhe_pmtu = 0; 1295 fnhe->fnhe_expires = 0; 1296 fnhe_flush_routes(fnhe); 1297 orig = NULL; 1298 } 1299 fill_route_from_fnhe(rt, fnhe); 1300 if (!rt->rt_gateway) 1301 rt->rt_gateway = daddr; 1302 1303 if (!(rt->dst.flags & DST_NOCACHE)) { 1304 rcu_assign_pointer(*porig, rt); 1305 if (orig) 1306 rt_free(orig); 1307 ret = true; 1308 } 1309 1310 fnhe->fnhe_stamp = jiffies; 1311 } 1312 spin_unlock_bh(&fnhe_lock); 1313 1314 return ret; 1315 } 1316 1317 static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt) 1318 { 1319 struct rtable *orig, *prev, **p; 1320 bool ret = true; 1321 1322 if (rt_is_input_route(rt)) { 1323 p = (struct rtable **)&nh->nh_rth_input; 1324 } else { 1325 p = (struct rtable **)raw_cpu_ptr(nh->nh_pcpu_rth_output); 1326 } 1327 orig = *p; 1328 1329 prev = cmpxchg(p, orig, rt); 1330 if (prev == orig) { 1331 if (orig) 1332 rt_free(orig); 1333 } else 1334 ret = false; 1335 1336 return ret; 1337 } 1338 1339 struct uncached_list { 1340 spinlock_t lock; 1341 struct list_head head; 1342 }; 1343 1344 static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list); 1345 1346 static void rt_add_uncached_list(struct rtable *rt) 1347 { 1348 struct uncached_list *ul = raw_cpu_ptr(&rt_uncached_list); 1349 1350 rt->rt_uncached_list = ul; 1351 1352 spin_lock_bh(&ul->lock); 1353 list_add_tail(&rt->rt_uncached, &ul->head); 1354 spin_unlock_bh(&ul->lock); 1355 } 1356 1357 static void ipv4_dst_destroy(struct dst_entry *dst) 1358 { 1359 struct rtable *rt = (struct rtable *) dst; 1360 1361 if (!list_empty(&rt->rt_uncached)) { 1362 struct uncached_list *ul = rt->rt_uncached_list; 1363 1364 spin_lock_bh(&ul->lock); 1365 list_del(&rt->rt_uncached); 1366 spin_unlock_bh(&ul->lock); 1367 } 1368 } 1369 1370 void rt_flush_dev(struct net_device *dev) 1371 { 1372 struct net *net = dev_net(dev); 1373 struct rtable *rt; 1374 int cpu; 1375 1376 for_each_possible_cpu(cpu) { 1377 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 1378 1379 spin_lock_bh(&ul->lock); 1380 list_for_each_entry(rt, &ul->head, rt_uncached) { 1381 if (rt->dst.dev != dev) 1382 continue; 1383 rt->dst.dev = net->loopback_dev; 1384 dev_hold(rt->dst.dev); 1385 dev_put(dev); 1386 } 1387 spin_unlock_bh(&ul->lock); 1388 } 1389 } 1390 1391 static bool rt_cache_valid(const struct rtable *rt) 1392 { 1393 return rt && 1394 rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK && 1395 !rt_is_expired(rt); 1396 } 1397 1398 static void rt_set_nexthop(struct rtable *rt, __be32 daddr, 1399 const struct fib_result *res, 1400 struct fib_nh_exception *fnhe, 1401 struct fib_info *fi, u16 type, u32 itag) 1402 { 1403 bool cached = false; 1404 1405 if (fi) { 1406 struct fib_nh *nh = &FIB_RES_NH(*res); 1407 1408 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) { 1409 rt->rt_gateway = nh->nh_gw; 1410 rt->rt_uses_gateway = 1; 1411 } 1412 dst_init_metrics(&rt->dst, fi->fib_metrics, true); 1413 #ifdef CONFIG_IP_ROUTE_CLASSID 1414 rt->dst.tclassid = nh->nh_tclassid; 1415 #endif 1416 rt->dst.lwtstate = lwtstate_get(nh->nh_lwtstate); 1417 if (unlikely(fnhe)) 1418 cached = rt_bind_exception(rt, fnhe, daddr); 1419 else if (!(rt->dst.flags & DST_NOCACHE)) 1420 cached = rt_cache_route(nh, rt); 1421 if (unlikely(!cached)) { 1422 /* Routes we intend to cache in nexthop exception or 1423 * FIB nexthop have the DST_NOCACHE bit clear. 1424 * However, if we are unsuccessful at storing this 1425 * route into the cache we really need to set it. 1426 */ 1427 rt->dst.flags |= DST_NOCACHE; 1428 if (!rt->rt_gateway) 1429 rt->rt_gateway = daddr; 1430 rt_add_uncached_list(rt); 1431 } 1432 } else 1433 rt_add_uncached_list(rt); 1434 1435 #ifdef CONFIG_IP_ROUTE_CLASSID 1436 #ifdef CONFIG_IP_MULTIPLE_TABLES 1437 set_class_tag(rt, res->tclassid); 1438 #endif 1439 set_class_tag(rt, itag); 1440 #endif 1441 } 1442 1443 struct rtable *rt_dst_alloc(struct net_device *dev, 1444 unsigned int flags, u16 type, 1445 bool nopolicy, bool noxfrm, bool will_cache) 1446 { 1447 struct rtable *rt; 1448 1449 rt = dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK, 1450 (will_cache ? 0 : (DST_HOST | DST_NOCACHE)) | 1451 (nopolicy ? DST_NOPOLICY : 0) | 1452 (noxfrm ? DST_NOXFRM : 0)); 1453 1454 if (rt) { 1455 rt->rt_genid = rt_genid_ipv4(dev_net(dev)); 1456 rt->rt_flags = flags; 1457 rt->rt_type = type; 1458 rt->rt_is_input = 0; 1459 rt->rt_iif = 0; 1460 rt->rt_pmtu = 0; 1461 rt->rt_gateway = 0; 1462 rt->rt_uses_gateway = 0; 1463 rt->rt_table_id = 0; 1464 INIT_LIST_HEAD(&rt->rt_uncached); 1465 1466 rt->dst.output = ip_output; 1467 if (flags & RTCF_LOCAL) 1468 rt->dst.input = ip_local_deliver; 1469 } 1470 1471 return rt; 1472 } 1473 EXPORT_SYMBOL(rt_dst_alloc); 1474 1475 /* called in rcu_read_lock() section */ 1476 static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1477 u8 tos, struct net_device *dev, int our) 1478 { 1479 struct rtable *rth; 1480 struct in_device *in_dev = __in_dev_get_rcu(dev); 1481 unsigned int flags = RTCF_MULTICAST; 1482 u32 itag = 0; 1483 int err; 1484 1485 /* Primary sanity checks. */ 1486 1487 if (!in_dev) 1488 return -EINVAL; 1489 1490 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) || 1491 skb->protocol != htons(ETH_P_IP)) 1492 goto e_inval; 1493 1494 if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev)) 1495 goto e_inval; 1496 1497 if (ipv4_is_zeronet(saddr)) { 1498 if (!ipv4_is_local_multicast(daddr)) 1499 goto e_inval; 1500 } else { 1501 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1502 in_dev, &itag); 1503 if (err < 0) 1504 goto e_err; 1505 } 1506 if (our) 1507 flags |= RTCF_LOCAL; 1508 1509 rth = rt_dst_alloc(dev_net(dev)->loopback_dev, flags, RTN_MULTICAST, 1510 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, false); 1511 if (!rth) 1512 goto e_nobufs; 1513 1514 #ifdef CONFIG_IP_ROUTE_CLASSID 1515 rth->dst.tclassid = itag; 1516 #endif 1517 rth->dst.output = ip_rt_bug; 1518 rth->rt_is_input= 1; 1519 1520 #ifdef CONFIG_IP_MROUTE 1521 if (!ipv4_is_local_multicast(daddr) && IN_DEV_MFORWARD(in_dev)) 1522 rth->dst.input = ip_mr_input; 1523 #endif 1524 RT_CACHE_STAT_INC(in_slow_mc); 1525 1526 skb_dst_set(skb, &rth->dst); 1527 return 0; 1528 1529 e_nobufs: 1530 return -ENOBUFS; 1531 e_inval: 1532 return -EINVAL; 1533 e_err: 1534 return err; 1535 } 1536 1537 1538 static void ip_handle_martian_source(struct net_device *dev, 1539 struct in_device *in_dev, 1540 struct sk_buff *skb, 1541 __be32 daddr, 1542 __be32 saddr) 1543 { 1544 RT_CACHE_STAT_INC(in_martian_src); 1545 #ifdef CONFIG_IP_ROUTE_VERBOSE 1546 if (IN_DEV_LOG_MARTIANS(in_dev) && net_ratelimit()) { 1547 /* 1548 * RFC1812 recommendation, if source is martian, 1549 * the only hint is MAC header. 1550 */ 1551 pr_warn("martian source %pI4 from %pI4, on dev %s\n", 1552 &daddr, &saddr, dev->name); 1553 if (dev->hard_header_len && skb_mac_header_was_set(skb)) { 1554 print_hex_dump(KERN_WARNING, "ll header: ", 1555 DUMP_PREFIX_OFFSET, 16, 1, 1556 skb_mac_header(skb), 1557 dev->hard_header_len, true); 1558 } 1559 } 1560 #endif 1561 } 1562 1563 static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr) 1564 { 1565 struct fnhe_hash_bucket *hash; 1566 struct fib_nh_exception *fnhe, __rcu **fnhe_p; 1567 u32 hval = fnhe_hashfun(daddr); 1568 1569 spin_lock_bh(&fnhe_lock); 1570 1571 hash = rcu_dereference_protected(nh->nh_exceptions, 1572 lockdep_is_held(&fnhe_lock)); 1573 hash += hval; 1574 1575 fnhe_p = &hash->chain; 1576 fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock)); 1577 while (fnhe) { 1578 if (fnhe->fnhe_daddr == daddr) { 1579 rcu_assign_pointer(*fnhe_p, rcu_dereference_protected( 1580 fnhe->fnhe_next, lockdep_is_held(&fnhe_lock))); 1581 fnhe_flush_routes(fnhe); 1582 kfree_rcu(fnhe, rcu); 1583 break; 1584 } 1585 fnhe_p = &fnhe->fnhe_next; 1586 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1587 lockdep_is_held(&fnhe_lock)); 1588 } 1589 1590 spin_unlock_bh(&fnhe_lock); 1591 } 1592 1593 /* called in rcu_read_lock() section */ 1594 static int __mkroute_input(struct sk_buff *skb, 1595 const struct fib_result *res, 1596 struct in_device *in_dev, 1597 __be32 daddr, __be32 saddr, u32 tos) 1598 { 1599 struct fib_nh_exception *fnhe; 1600 struct rtable *rth; 1601 int err; 1602 struct in_device *out_dev; 1603 bool do_cache; 1604 u32 itag = 0; 1605 1606 /* get a working reference to the output device */ 1607 out_dev = __in_dev_get_rcu(FIB_RES_DEV(*res)); 1608 if (!out_dev) { 1609 net_crit_ratelimited("Bug in ip_route_input_slow(). Please report.\n"); 1610 return -EINVAL; 1611 } 1612 1613 err = fib_validate_source(skb, saddr, daddr, tos, FIB_RES_OIF(*res), 1614 in_dev->dev, in_dev, &itag); 1615 if (err < 0) { 1616 ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr, 1617 saddr); 1618 1619 goto cleanup; 1620 } 1621 1622 do_cache = res->fi && !itag; 1623 if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) && 1624 skb->protocol == htons(ETH_P_IP) && 1625 (IN_DEV_SHARED_MEDIA(out_dev) || 1626 inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res)))) 1627 IPCB(skb)->flags |= IPSKB_DOREDIRECT; 1628 1629 if (skb->protocol != htons(ETH_P_IP)) { 1630 /* Not IP (i.e. ARP). Do not create route, if it is 1631 * invalid for proxy arp. DNAT routes are always valid. 1632 * 1633 * Proxy arp feature have been extended to allow, ARP 1634 * replies back to the same interface, to support 1635 * Private VLAN switch technologies. See arp.c. 1636 */ 1637 if (out_dev == in_dev && 1638 IN_DEV_PROXY_ARP_PVLAN(in_dev) == 0) { 1639 err = -EINVAL; 1640 goto cleanup; 1641 } 1642 } 1643 1644 fnhe = find_exception(&FIB_RES_NH(*res), daddr); 1645 if (do_cache) { 1646 if (fnhe) { 1647 rth = rcu_dereference(fnhe->fnhe_rth_input); 1648 if (rth && rth->dst.expires && 1649 time_after(jiffies, rth->dst.expires)) { 1650 ip_del_fnhe(&FIB_RES_NH(*res), daddr); 1651 fnhe = NULL; 1652 } else { 1653 goto rt_cache; 1654 } 1655 } 1656 1657 rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input); 1658 1659 rt_cache: 1660 if (rt_cache_valid(rth)) { 1661 skb_dst_set_noref(skb, &rth->dst); 1662 goto out; 1663 } 1664 } 1665 1666 rth = rt_dst_alloc(out_dev->dev, 0, res->type, 1667 IN_DEV_CONF_GET(in_dev, NOPOLICY), 1668 IN_DEV_CONF_GET(out_dev, NOXFRM), do_cache); 1669 if (!rth) { 1670 err = -ENOBUFS; 1671 goto cleanup; 1672 } 1673 1674 rth->rt_is_input = 1; 1675 if (res->table) 1676 rth->rt_table_id = res->table->tb_id; 1677 RT_CACHE_STAT_INC(in_slow_tot); 1678 1679 rth->dst.input = ip_forward; 1680 1681 rt_set_nexthop(rth, daddr, res, fnhe, res->fi, res->type, itag); 1682 if (lwtunnel_output_redirect(rth->dst.lwtstate)) { 1683 rth->dst.lwtstate->orig_output = rth->dst.output; 1684 rth->dst.output = lwtunnel_output; 1685 } 1686 if (lwtunnel_input_redirect(rth->dst.lwtstate)) { 1687 rth->dst.lwtstate->orig_input = rth->dst.input; 1688 rth->dst.input = lwtunnel_input; 1689 } 1690 skb_dst_set(skb, &rth->dst); 1691 out: 1692 err = 0; 1693 cleanup: 1694 return err; 1695 } 1696 1697 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1698 1699 /* To make ICMP packets follow the right flow, the multipath hash is 1700 * calculated from the inner IP addresses in reverse order. 1701 */ 1702 static int ip_multipath_icmp_hash(struct sk_buff *skb) 1703 { 1704 const struct iphdr *outer_iph = ip_hdr(skb); 1705 struct icmphdr _icmph; 1706 const struct icmphdr *icmph; 1707 struct iphdr _inner_iph; 1708 const struct iphdr *inner_iph; 1709 1710 if (unlikely((outer_iph->frag_off & htons(IP_OFFSET)) != 0)) 1711 goto standard_hash; 1712 1713 icmph = skb_header_pointer(skb, outer_iph->ihl * 4, sizeof(_icmph), 1714 &_icmph); 1715 if (!icmph) 1716 goto standard_hash; 1717 1718 if (icmph->type != ICMP_DEST_UNREACH && 1719 icmph->type != ICMP_REDIRECT && 1720 icmph->type != ICMP_TIME_EXCEEDED && 1721 icmph->type != ICMP_PARAMETERPROB) { 1722 goto standard_hash; 1723 } 1724 1725 inner_iph = skb_header_pointer(skb, 1726 outer_iph->ihl * 4 + sizeof(_icmph), 1727 sizeof(_inner_iph), &_inner_iph); 1728 if (!inner_iph) 1729 goto standard_hash; 1730 1731 return fib_multipath_hash(inner_iph->daddr, inner_iph->saddr); 1732 1733 standard_hash: 1734 return fib_multipath_hash(outer_iph->saddr, outer_iph->daddr); 1735 } 1736 1737 #endif /* CONFIG_IP_ROUTE_MULTIPATH */ 1738 1739 static int ip_mkroute_input(struct sk_buff *skb, 1740 struct fib_result *res, 1741 const struct flowi4 *fl4, 1742 struct in_device *in_dev, 1743 __be32 daddr, __be32 saddr, u32 tos) 1744 { 1745 #ifdef CONFIG_IP_ROUTE_MULTIPATH 1746 if (res->fi && res->fi->fib_nhs > 1) { 1747 int h; 1748 1749 if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP)) 1750 h = ip_multipath_icmp_hash(skb); 1751 else 1752 h = fib_multipath_hash(saddr, daddr); 1753 fib_select_multipath(res, h); 1754 } 1755 #endif 1756 1757 /* create a routing cache entry */ 1758 return __mkroute_input(skb, res, in_dev, daddr, saddr, tos); 1759 } 1760 1761 /* 1762 * NOTE. We drop all the packets that has local source 1763 * addresses, because every properly looped back packet 1764 * must have correct destination already attached by output routine. 1765 * 1766 * Such approach solves two big problems: 1767 * 1. Not simplex devices are handled properly. 1768 * 2. IP spoofing attempts are filtered with 100% of guarantee. 1769 * called with rcu_read_lock() 1770 */ 1771 1772 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1773 u8 tos, struct net_device *dev) 1774 { 1775 struct fib_result res; 1776 struct in_device *in_dev = __in_dev_get_rcu(dev); 1777 struct ip_tunnel_info *tun_info; 1778 struct flowi4 fl4; 1779 unsigned int flags = 0; 1780 u32 itag = 0; 1781 struct rtable *rth; 1782 int err = -EINVAL; 1783 struct net *net = dev_net(dev); 1784 bool do_cache; 1785 1786 /* IP on this device is disabled. */ 1787 1788 if (!in_dev) 1789 goto out; 1790 1791 /* Check for the most weird martians, which can be not detected 1792 by fib_lookup. 1793 */ 1794 1795 tun_info = skb_tunnel_info(skb); 1796 if (tun_info && !(tun_info->mode & IP_TUNNEL_INFO_TX)) 1797 fl4.flowi4_tun_key.tun_id = tun_info->key.tun_id; 1798 else 1799 fl4.flowi4_tun_key.tun_id = 0; 1800 skb_dst_drop(skb); 1801 1802 if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr)) 1803 goto martian_source; 1804 1805 res.fi = NULL; 1806 res.table = NULL; 1807 if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0)) 1808 goto brd_input; 1809 1810 /* Accept zero addresses only to limited broadcast; 1811 * I even do not know to fix it or not. Waiting for complains :-) 1812 */ 1813 if (ipv4_is_zeronet(saddr)) 1814 goto martian_source; 1815 1816 if (ipv4_is_zeronet(daddr)) 1817 goto martian_destination; 1818 1819 /* Following code try to avoid calling IN_DEV_NET_ROUTE_LOCALNET(), 1820 * and call it once if daddr or/and saddr are loopback addresses 1821 */ 1822 if (ipv4_is_loopback(daddr)) { 1823 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1824 goto martian_destination; 1825 } else if (ipv4_is_loopback(saddr)) { 1826 if (!IN_DEV_NET_ROUTE_LOCALNET(in_dev, net)) 1827 goto martian_source; 1828 } 1829 1830 /* 1831 * Now we are ready to route packet. 1832 */ 1833 fl4.flowi4_oif = 0; 1834 fl4.flowi4_iif = l3mdev_fib_oif_rcu(dev); 1835 fl4.flowi4_mark = skb->mark; 1836 fl4.flowi4_tos = tos; 1837 fl4.flowi4_scope = RT_SCOPE_UNIVERSE; 1838 fl4.flowi4_flags = 0; 1839 fl4.daddr = daddr; 1840 fl4.saddr = saddr; 1841 err = fib_lookup(net, &fl4, &res, 0); 1842 if (err != 0) { 1843 if (!IN_DEV_FORWARD(in_dev)) 1844 err = -EHOSTUNREACH; 1845 goto no_route; 1846 } 1847 1848 if (res.type == RTN_BROADCAST) 1849 goto brd_input; 1850 1851 if (res.type == RTN_LOCAL) { 1852 err = fib_validate_source(skb, saddr, daddr, tos, 1853 0, dev, in_dev, &itag); 1854 if (err < 0) 1855 goto martian_source; 1856 goto local_input; 1857 } 1858 1859 if (!IN_DEV_FORWARD(in_dev)) { 1860 err = -EHOSTUNREACH; 1861 goto no_route; 1862 } 1863 if (res.type != RTN_UNICAST) 1864 goto martian_destination; 1865 1866 err = ip_mkroute_input(skb, &res, &fl4, in_dev, daddr, saddr, tos); 1867 out: return err; 1868 1869 brd_input: 1870 if (skb->protocol != htons(ETH_P_IP)) 1871 goto e_inval; 1872 1873 if (!ipv4_is_zeronet(saddr)) { 1874 err = fib_validate_source(skb, saddr, 0, tos, 0, dev, 1875 in_dev, &itag); 1876 if (err < 0) 1877 goto martian_source; 1878 } 1879 flags |= RTCF_BROADCAST; 1880 res.type = RTN_BROADCAST; 1881 RT_CACHE_STAT_INC(in_brd); 1882 1883 local_input: 1884 do_cache = false; 1885 if (res.fi) { 1886 if (!itag) { 1887 rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input); 1888 if (rt_cache_valid(rth)) { 1889 skb_dst_set_noref(skb, &rth->dst); 1890 err = 0; 1891 goto out; 1892 } 1893 do_cache = true; 1894 } 1895 } 1896 1897 rth = rt_dst_alloc(net->loopback_dev, flags | RTCF_LOCAL, res.type, 1898 IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache); 1899 if (!rth) 1900 goto e_nobufs; 1901 1902 rth->dst.output= ip_rt_bug; 1903 #ifdef CONFIG_IP_ROUTE_CLASSID 1904 rth->dst.tclassid = itag; 1905 #endif 1906 rth->rt_is_input = 1; 1907 if (res.table) 1908 rth->rt_table_id = res.table->tb_id; 1909 1910 RT_CACHE_STAT_INC(in_slow_tot); 1911 if (res.type == RTN_UNREACHABLE) { 1912 rth->dst.input= ip_error; 1913 rth->dst.error= -err; 1914 rth->rt_flags &= ~RTCF_LOCAL; 1915 } 1916 if (do_cache) { 1917 if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) { 1918 rth->dst.flags |= DST_NOCACHE; 1919 rt_add_uncached_list(rth); 1920 } 1921 } 1922 skb_dst_set(skb, &rth->dst); 1923 err = 0; 1924 goto out; 1925 1926 no_route: 1927 RT_CACHE_STAT_INC(in_no_route); 1928 res.type = RTN_UNREACHABLE; 1929 res.fi = NULL; 1930 res.table = NULL; 1931 goto local_input; 1932 1933 /* 1934 * Do not cache martian addresses: they should be logged (RFC1812) 1935 */ 1936 martian_destination: 1937 RT_CACHE_STAT_INC(in_martian_dst); 1938 #ifdef CONFIG_IP_ROUTE_VERBOSE 1939 if (IN_DEV_LOG_MARTIANS(in_dev)) 1940 net_warn_ratelimited("martian destination %pI4 from %pI4, dev %s\n", 1941 &daddr, &saddr, dev->name); 1942 #endif 1943 1944 e_inval: 1945 err = -EINVAL; 1946 goto out; 1947 1948 e_nobufs: 1949 err = -ENOBUFS; 1950 goto out; 1951 1952 martian_source: 1953 ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); 1954 goto out; 1955 } 1956 1957 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 1958 u8 tos, struct net_device *dev) 1959 { 1960 int res; 1961 1962 rcu_read_lock(); 1963 1964 /* Multicast recognition logic is moved from route cache to here. 1965 The problem was that too many Ethernet cards have broken/missing 1966 hardware multicast filters :-( As result the host on multicasting 1967 network acquires a lot of useless route cache entries, sort of 1968 SDR messages from all the world. Now we try to get rid of them. 1969 Really, provided software IP multicast filter is organized 1970 reasonably (at least, hashed), it does not result in a slowdown 1971 comparing with route cache reject entries. 1972 Note, that multicast routers are not affected, because 1973 route cache entry is created eventually. 1974 */ 1975 if (ipv4_is_multicast(daddr)) { 1976 struct in_device *in_dev = __in_dev_get_rcu(dev); 1977 1978 if (in_dev) { 1979 int our = ip_check_mc_rcu(in_dev, daddr, saddr, 1980 ip_hdr(skb)->protocol); 1981 if (our 1982 #ifdef CONFIG_IP_MROUTE 1983 || 1984 (!ipv4_is_local_multicast(daddr) && 1985 IN_DEV_MFORWARD(in_dev)) 1986 #endif 1987 ) { 1988 int res = ip_route_input_mc(skb, daddr, saddr, 1989 tos, dev, our); 1990 rcu_read_unlock(); 1991 return res; 1992 } 1993 } 1994 rcu_read_unlock(); 1995 return -EINVAL; 1996 } 1997 res = ip_route_input_slow(skb, daddr, saddr, tos, dev); 1998 rcu_read_unlock(); 1999 return res; 2000 } 2001 EXPORT_SYMBOL(ip_route_input_noref); 2002 2003 /* called with rcu_read_lock() */ 2004 static struct rtable *__mkroute_output(const struct fib_result *res, 2005 const struct flowi4 *fl4, int orig_oif, 2006 struct net_device *dev_out, 2007 unsigned int flags) 2008 { 2009 struct fib_info *fi = res->fi; 2010 struct fib_nh_exception *fnhe; 2011 struct in_device *in_dev; 2012 u16 type = res->type; 2013 struct rtable *rth; 2014 bool do_cache; 2015 2016 in_dev = __in_dev_get_rcu(dev_out); 2017 if (!in_dev) 2018 return ERR_PTR(-EINVAL); 2019 2020 if (likely(!IN_DEV_ROUTE_LOCALNET(in_dev))) 2021 if (ipv4_is_loopback(fl4->saddr) && !(dev_out->flags & IFF_LOOPBACK)) 2022 return ERR_PTR(-EINVAL); 2023 2024 if (ipv4_is_lbcast(fl4->daddr)) 2025 type = RTN_BROADCAST; 2026 else if (ipv4_is_multicast(fl4->daddr)) 2027 type = RTN_MULTICAST; 2028 else if (ipv4_is_zeronet(fl4->daddr)) 2029 return ERR_PTR(-EINVAL); 2030 2031 if (dev_out->flags & IFF_LOOPBACK) 2032 flags |= RTCF_LOCAL; 2033 2034 do_cache = true; 2035 if (type == RTN_BROADCAST) { 2036 flags |= RTCF_BROADCAST | RTCF_LOCAL; 2037 fi = NULL; 2038 } else if (type == RTN_MULTICAST) { 2039 flags |= RTCF_MULTICAST | RTCF_LOCAL; 2040 if (!ip_check_mc_rcu(in_dev, fl4->daddr, fl4->saddr, 2041 fl4->flowi4_proto)) 2042 flags &= ~RTCF_LOCAL; 2043 else 2044 do_cache = false; 2045 /* If multicast route do not exist use 2046 * default one, but do not gateway in this case. 2047 * Yes, it is hack. 2048 */ 2049 if (fi && res->prefixlen < 4) 2050 fi = NULL; 2051 } else if ((type == RTN_LOCAL) && (orig_oif != 0) && 2052 (orig_oif != dev_out->ifindex)) { 2053 /* For local routes that require a particular output interface 2054 * we do not want to cache the result. Caching the result 2055 * causes incorrect behaviour when there are multiple source 2056 * addresses on the interface, the end result being that if the 2057 * intended recipient is waiting on that interface for the 2058 * packet he won't receive it because it will be delivered on 2059 * the loopback interface and the IP_PKTINFO ipi_ifindex will 2060 * be set to the loopback interface as well. 2061 */ 2062 fi = NULL; 2063 } 2064 2065 fnhe = NULL; 2066 do_cache &= fi != NULL; 2067 if (do_cache) { 2068 struct rtable __rcu **prth; 2069 struct fib_nh *nh = &FIB_RES_NH(*res); 2070 2071 fnhe = find_exception(nh, fl4->daddr); 2072 if (fnhe) { 2073 prth = &fnhe->fnhe_rth_output; 2074 rth = rcu_dereference(*prth); 2075 if (rth && rth->dst.expires && 2076 time_after(jiffies, rth->dst.expires)) { 2077 ip_del_fnhe(nh, fl4->daddr); 2078 fnhe = NULL; 2079 } else { 2080 goto rt_cache; 2081 } 2082 } 2083 2084 if (unlikely(fl4->flowi4_flags & 2085 FLOWI_FLAG_KNOWN_NH && 2086 !(nh->nh_gw && 2087 nh->nh_scope == RT_SCOPE_LINK))) { 2088 do_cache = false; 2089 goto add; 2090 } 2091 prth = raw_cpu_ptr(nh->nh_pcpu_rth_output); 2092 rth = rcu_dereference(*prth); 2093 2094 rt_cache: 2095 if (rt_cache_valid(rth)) { 2096 dst_hold(&rth->dst); 2097 return rth; 2098 } 2099 } 2100 2101 add: 2102 rth = rt_dst_alloc(dev_out, flags, type, 2103 IN_DEV_CONF_GET(in_dev, NOPOLICY), 2104 IN_DEV_CONF_GET(in_dev, NOXFRM), 2105 do_cache); 2106 if (!rth) 2107 return ERR_PTR(-ENOBUFS); 2108 2109 rth->rt_iif = orig_oif ? : 0; 2110 if (res->table) 2111 rth->rt_table_id = res->table->tb_id; 2112 2113 RT_CACHE_STAT_INC(out_slow_tot); 2114 2115 if (flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { 2116 if (flags & RTCF_LOCAL && 2117 !(dev_out->flags & IFF_LOOPBACK)) { 2118 rth->dst.output = ip_mc_output; 2119 RT_CACHE_STAT_INC(out_slow_mc); 2120 } 2121 #ifdef CONFIG_IP_MROUTE 2122 if (type == RTN_MULTICAST) { 2123 if (IN_DEV_MFORWARD(in_dev) && 2124 !ipv4_is_local_multicast(fl4->daddr)) { 2125 rth->dst.input = ip_mr_input; 2126 rth->dst.output = ip_mc_output; 2127 } 2128 } 2129 #endif 2130 } 2131 2132 rt_set_nexthop(rth, fl4->daddr, res, fnhe, fi, type, 0); 2133 if (lwtunnel_output_redirect(rth->dst.lwtstate)) 2134 rth->dst.output = lwtunnel_output; 2135 2136 return rth; 2137 } 2138 2139 /* 2140 * Major route resolver routine. 2141 */ 2142 2143 struct rtable *__ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, 2144 int mp_hash) 2145 { 2146 struct net_device *dev_out = NULL; 2147 __u8 tos = RT_FL_TOS(fl4); 2148 unsigned int flags = 0; 2149 struct fib_result res; 2150 struct rtable *rth; 2151 int master_idx; 2152 int orig_oif; 2153 int err = -ENETUNREACH; 2154 2155 res.tclassid = 0; 2156 res.fi = NULL; 2157 res.table = NULL; 2158 2159 orig_oif = fl4->flowi4_oif; 2160 2161 master_idx = l3mdev_master_ifindex_by_index(net, fl4->flowi4_oif); 2162 if (master_idx) 2163 fl4->flowi4_oif = master_idx; 2164 fl4->flowi4_iif = LOOPBACK_IFINDEX; 2165 fl4->flowi4_tos = tos & IPTOS_RT_MASK; 2166 fl4->flowi4_scope = ((tos & RTO_ONLINK) ? 2167 RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); 2168 2169 rcu_read_lock(); 2170 if (fl4->saddr) { 2171 rth = ERR_PTR(-EINVAL); 2172 if (ipv4_is_multicast(fl4->saddr) || 2173 ipv4_is_lbcast(fl4->saddr) || 2174 ipv4_is_zeronet(fl4->saddr)) 2175 goto out; 2176 2177 /* I removed check for oif == dev_out->oif here. 2178 It was wrong for two reasons: 2179 1. ip_dev_find(net, saddr) can return wrong iface, if saddr 2180 is assigned to multiple interfaces. 2181 2. Moreover, we are allowed to send packets with saddr 2182 of another iface. --ANK 2183 */ 2184 2185 if (fl4->flowi4_oif == 0 && 2186 (ipv4_is_multicast(fl4->daddr) || 2187 ipv4_is_lbcast(fl4->daddr))) { 2188 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2189 dev_out = __ip_dev_find(net, fl4->saddr, false); 2190 if (!dev_out) 2191 goto out; 2192 2193 /* Special hack: user can direct multicasts 2194 and limited broadcast via necessary interface 2195 without fiddling with IP_MULTICAST_IF or IP_PKTINFO. 2196 This hack is not just for fun, it allows 2197 vic,vat and friends to work. 2198 They bind socket to loopback, set ttl to zero 2199 and expect that it will work. 2200 From the viewpoint of routing cache they are broken, 2201 because we are not allowed to build multicast path 2202 with loopback source addr (look, routing cache 2203 cannot know, that ttl is zero, so that packet 2204 will not leave this host and route is valid). 2205 Luckily, this hack is good workaround. 2206 */ 2207 2208 fl4->flowi4_oif = dev_out->ifindex; 2209 goto make_route; 2210 } 2211 2212 if (!(fl4->flowi4_flags & FLOWI_FLAG_ANYSRC)) { 2213 /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */ 2214 if (!__ip_dev_find(net, fl4->saddr, false)) 2215 goto out; 2216 } 2217 } 2218 2219 2220 if (fl4->flowi4_oif) { 2221 dev_out = dev_get_by_index_rcu(net, fl4->flowi4_oif); 2222 rth = ERR_PTR(-ENODEV); 2223 if (!dev_out) 2224 goto out; 2225 2226 /* RACE: Check return value of inet_select_addr instead. */ 2227 if (!(dev_out->flags & IFF_UP) || !__in_dev_get_rcu(dev_out)) { 2228 rth = ERR_PTR(-ENETUNREACH); 2229 goto out; 2230 } 2231 if (ipv4_is_local_multicast(fl4->daddr) || 2232 ipv4_is_lbcast(fl4->daddr) || 2233 fl4->flowi4_proto == IPPROTO_IGMP) { 2234 if (!fl4->saddr) 2235 fl4->saddr = inet_select_addr(dev_out, 0, 2236 RT_SCOPE_LINK); 2237 goto make_route; 2238 } 2239 if (!fl4->saddr) { 2240 if (ipv4_is_multicast(fl4->daddr)) 2241 fl4->saddr = inet_select_addr(dev_out, 0, 2242 fl4->flowi4_scope); 2243 else if (!fl4->daddr) 2244 fl4->saddr = inet_select_addr(dev_out, 0, 2245 RT_SCOPE_HOST); 2246 } 2247 2248 rth = l3mdev_get_rtable(dev_out, fl4); 2249 if (rth) 2250 goto out; 2251 } 2252 2253 if (!fl4->daddr) { 2254 fl4->daddr = fl4->saddr; 2255 if (!fl4->daddr) 2256 fl4->daddr = fl4->saddr = htonl(INADDR_LOOPBACK); 2257 dev_out = net->loopback_dev; 2258 fl4->flowi4_oif = LOOPBACK_IFINDEX; 2259 res.type = RTN_LOCAL; 2260 flags |= RTCF_LOCAL; 2261 goto make_route; 2262 } 2263 2264 err = fib_lookup(net, fl4, &res, 0); 2265 if (err) { 2266 res.fi = NULL; 2267 res.table = NULL; 2268 if (fl4->flowi4_oif && 2269 !netif_index_is_l3_master(net, fl4->flowi4_oif)) { 2270 /* Apparently, routing tables are wrong. Assume, 2271 that the destination is on link. 2272 2273 WHY? DW. 2274 Because we are allowed to send to iface 2275 even if it has NO routes and NO assigned 2276 addresses. When oif is specified, routing 2277 tables are looked up with only one purpose: 2278 to catch if destination is gatewayed, rather than 2279 direct. Moreover, if MSG_DONTROUTE is set, 2280 we send packet, ignoring both routing tables 2281 and ifaddr state. --ANK 2282 2283 2284 We could make it even if oif is unknown, 2285 likely IPv6, but we do not. 2286 */ 2287 2288 if (fl4->saddr == 0) 2289 fl4->saddr = inet_select_addr(dev_out, 0, 2290 RT_SCOPE_LINK); 2291 res.type = RTN_UNICAST; 2292 goto make_route; 2293 } 2294 rth = ERR_PTR(err); 2295 goto out; 2296 } 2297 2298 if (res.type == RTN_LOCAL) { 2299 if (!fl4->saddr) { 2300 if (res.fi->fib_prefsrc) 2301 fl4->saddr = res.fi->fib_prefsrc; 2302 else 2303 fl4->saddr = fl4->daddr; 2304 } 2305 dev_out = net->loopback_dev; 2306 fl4->flowi4_oif = dev_out->ifindex; 2307 flags |= RTCF_LOCAL; 2308 goto make_route; 2309 } 2310 2311 fib_select_path(net, &res, fl4, mp_hash); 2312 2313 dev_out = FIB_RES_DEV(res); 2314 fl4->flowi4_oif = dev_out->ifindex; 2315 2316 2317 make_route: 2318 rth = __mkroute_output(&res, fl4, orig_oif, dev_out, flags); 2319 2320 out: 2321 rcu_read_unlock(); 2322 return rth; 2323 } 2324 EXPORT_SYMBOL_GPL(__ip_route_output_key_hash); 2325 2326 static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie) 2327 { 2328 return NULL; 2329 } 2330 2331 static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst) 2332 { 2333 unsigned int mtu = dst_metric_raw(dst, RTAX_MTU); 2334 2335 return mtu ? : dst->dev->mtu; 2336 } 2337 2338 static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 2339 struct sk_buff *skb, u32 mtu) 2340 { 2341 } 2342 2343 static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 2344 struct sk_buff *skb) 2345 { 2346 } 2347 2348 static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst, 2349 unsigned long old) 2350 { 2351 return NULL; 2352 } 2353 2354 static struct dst_ops ipv4_dst_blackhole_ops = { 2355 .family = AF_INET, 2356 .check = ipv4_blackhole_dst_check, 2357 .mtu = ipv4_blackhole_mtu, 2358 .default_advmss = ipv4_default_advmss, 2359 .update_pmtu = ipv4_rt_blackhole_update_pmtu, 2360 .redirect = ipv4_rt_blackhole_redirect, 2361 .cow_metrics = ipv4_rt_blackhole_cow_metrics, 2362 .neigh_lookup = ipv4_neigh_lookup, 2363 }; 2364 2365 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig) 2366 { 2367 struct rtable *ort = (struct rtable *) dst_orig; 2368 struct rtable *rt; 2369 2370 rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0); 2371 if (rt) { 2372 struct dst_entry *new = &rt->dst; 2373 2374 new->__use = 1; 2375 new->input = dst_discard; 2376 new->output = dst_discard_out; 2377 2378 new->dev = ort->dst.dev; 2379 if (new->dev) 2380 dev_hold(new->dev); 2381 2382 rt->rt_is_input = ort->rt_is_input; 2383 rt->rt_iif = ort->rt_iif; 2384 rt->rt_pmtu = ort->rt_pmtu; 2385 2386 rt->rt_genid = rt_genid_ipv4(net); 2387 rt->rt_flags = ort->rt_flags; 2388 rt->rt_type = ort->rt_type; 2389 rt->rt_gateway = ort->rt_gateway; 2390 rt->rt_uses_gateway = ort->rt_uses_gateway; 2391 2392 INIT_LIST_HEAD(&rt->rt_uncached); 2393 dst_free(new); 2394 } 2395 2396 dst_release(dst_orig); 2397 2398 return rt ? &rt->dst : ERR_PTR(-ENOMEM); 2399 } 2400 2401 struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, 2402 const struct sock *sk) 2403 { 2404 struct rtable *rt = __ip_route_output_key(net, flp4); 2405 2406 if (IS_ERR(rt)) 2407 return rt; 2408 2409 if (flp4->flowi4_proto) 2410 rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, 2411 flowi4_to_flowi(flp4), 2412 sk, 0); 2413 2414 return rt; 2415 } 2416 EXPORT_SYMBOL_GPL(ip_route_output_flow); 2417 2418 static int rt_fill_info(struct net *net, __be32 dst, __be32 src, u32 table_id, 2419 struct flowi4 *fl4, struct sk_buff *skb, u32 portid, 2420 u32 seq, int event, int nowait, unsigned int flags) 2421 { 2422 struct rtable *rt = skb_rtable(skb); 2423 struct rtmsg *r; 2424 struct nlmsghdr *nlh; 2425 unsigned long expires = 0; 2426 u32 error; 2427 u32 metrics[RTAX_MAX]; 2428 2429 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags); 2430 if (!nlh) 2431 return -EMSGSIZE; 2432 2433 r = nlmsg_data(nlh); 2434 r->rtm_family = AF_INET; 2435 r->rtm_dst_len = 32; 2436 r->rtm_src_len = 0; 2437 r->rtm_tos = fl4->flowi4_tos; 2438 r->rtm_table = table_id; 2439 if (nla_put_u32(skb, RTA_TABLE, table_id)) 2440 goto nla_put_failure; 2441 r->rtm_type = rt->rt_type; 2442 r->rtm_scope = RT_SCOPE_UNIVERSE; 2443 r->rtm_protocol = RTPROT_UNSPEC; 2444 r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED; 2445 if (rt->rt_flags & RTCF_NOTIFY) 2446 r->rtm_flags |= RTM_F_NOTIFY; 2447 if (IPCB(skb)->flags & IPSKB_DOREDIRECT) 2448 r->rtm_flags |= RTCF_DOREDIRECT; 2449 2450 if (nla_put_in_addr(skb, RTA_DST, dst)) 2451 goto nla_put_failure; 2452 if (src) { 2453 r->rtm_src_len = 32; 2454 if (nla_put_in_addr(skb, RTA_SRC, src)) 2455 goto nla_put_failure; 2456 } 2457 if (rt->dst.dev && 2458 nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) 2459 goto nla_put_failure; 2460 #ifdef CONFIG_IP_ROUTE_CLASSID 2461 if (rt->dst.tclassid && 2462 nla_put_u32(skb, RTA_FLOW, rt->dst.tclassid)) 2463 goto nla_put_failure; 2464 #endif 2465 if (!rt_is_input_route(rt) && 2466 fl4->saddr != src) { 2467 if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr)) 2468 goto nla_put_failure; 2469 } 2470 if (rt->rt_uses_gateway && 2471 nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway)) 2472 goto nla_put_failure; 2473 2474 expires = rt->dst.expires; 2475 if (expires) { 2476 unsigned long now = jiffies; 2477 2478 if (time_before(now, expires)) 2479 expires -= now; 2480 else 2481 expires = 0; 2482 } 2483 2484 memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); 2485 if (rt->rt_pmtu && expires) 2486 metrics[RTAX_MTU - 1] = rt->rt_pmtu; 2487 if (rtnetlink_put_metrics(skb, metrics) < 0) 2488 goto nla_put_failure; 2489 2490 if (fl4->flowi4_mark && 2491 nla_put_u32(skb, RTA_MARK, fl4->flowi4_mark)) 2492 goto nla_put_failure; 2493 2494 error = rt->dst.error; 2495 2496 if (rt_is_input_route(rt)) { 2497 #ifdef CONFIG_IP_MROUTE 2498 if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) && 2499 IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { 2500 int err = ipmr_get_route(net, skb, 2501 fl4->saddr, fl4->daddr, 2502 r, nowait); 2503 if (err <= 0) { 2504 if (!nowait) { 2505 if (err == 0) 2506 return 0; 2507 goto nla_put_failure; 2508 } else { 2509 if (err == -EMSGSIZE) 2510 goto nla_put_failure; 2511 error = err; 2512 } 2513 } 2514 } else 2515 #endif 2516 if (nla_put_u32(skb, RTA_IIF, skb->dev->ifindex)) 2517 goto nla_put_failure; 2518 } 2519 2520 if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires, error) < 0) 2521 goto nla_put_failure; 2522 2523 nlmsg_end(skb, nlh); 2524 return 0; 2525 2526 nla_put_failure: 2527 nlmsg_cancel(skb, nlh); 2528 return -EMSGSIZE; 2529 } 2530 2531 static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh) 2532 { 2533 struct net *net = sock_net(in_skb->sk); 2534 struct rtmsg *rtm; 2535 struct nlattr *tb[RTA_MAX+1]; 2536 struct rtable *rt = NULL; 2537 struct flowi4 fl4; 2538 __be32 dst = 0; 2539 __be32 src = 0; 2540 u32 iif; 2541 int err; 2542 int mark; 2543 struct sk_buff *skb; 2544 u32 table_id = RT_TABLE_MAIN; 2545 2546 err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_ipv4_policy); 2547 if (err < 0) 2548 goto errout; 2549 2550 rtm = nlmsg_data(nlh); 2551 2552 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 2553 if (!skb) { 2554 err = -ENOBUFS; 2555 goto errout; 2556 } 2557 2558 /* Reserve room for dummy headers, this skb can pass 2559 through good chunk of routing engine. 2560 */ 2561 skb_reset_mac_header(skb); 2562 skb_reset_network_header(skb); 2563 2564 /* Bugfix: need to give ip_route_input enough of an IP header to not gag. */ 2565 ip_hdr(skb)->protocol = IPPROTO_ICMP; 2566 skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr)); 2567 2568 src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0; 2569 dst = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0; 2570 iif = tb[RTA_IIF] ? nla_get_u32(tb[RTA_IIF]) : 0; 2571 mark = tb[RTA_MARK] ? nla_get_u32(tb[RTA_MARK]) : 0; 2572 2573 memset(&fl4, 0, sizeof(fl4)); 2574 fl4.daddr = dst; 2575 fl4.saddr = src; 2576 fl4.flowi4_tos = rtm->rtm_tos; 2577 fl4.flowi4_oif = tb[RTA_OIF] ? nla_get_u32(tb[RTA_OIF]) : 0; 2578 fl4.flowi4_mark = mark; 2579 2580 if (netif_index_is_l3_master(net, fl4.flowi4_oif)) 2581 fl4.flowi4_flags = FLOWI_FLAG_L3MDEV_SRC | FLOWI_FLAG_SKIP_NH_OIF; 2582 2583 if (iif) { 2584 struct net_device *dev; 2585 2586 dev = __dev_get_by_index(net, iif); 2587 if (!dev) { 2588 err = -ENODEV; 2589 goto errout_free; 2590 } 2591 2592 skb->protocol = htons(ETH_P_IP); 2593 skb->dev = dev; 2594 skb->mark = mark; 2595 local_bh_disable(); 2596 err = ip_route_input(skb, dst, src, rtm->rtm_tos, dev); 2597 local_bh_enable(); 2598 2599 rt = skb_rtable(skb); 2600 if (err == 0 && rt->dst.error) 2601 err = -rt->dst.error; 2602 } else { 2603 rt = ip_route_output_key(net, &fl4); 2604 2605 err = 0; 2606 if (IS_ERR(rt)) 2607 err = PTR_ERR(rt); 2608 } 2609 2610 if (err) 2611 goto errout_free; 2612 2613 skb_dst_set(skb, &rt->dst); 2614 if (rtm->rtm_flags & RTM_F_NOTIFY) 2615 rt->rt_flags |= RTCF_NOTIFY; 2616 2617 if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE) 2618 table_id = rt->rt_table_id; 2619 2620 err = rt_fill_info(net, dst, src, table_id, &fl4, skb, 2621 NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, 2622 RTM_NEWROUTE, 0, 0); 2623 if (err < 0) 2624 goto errout_free; 2625 2626 err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); 2627 errout: 2628 return err; 2629 2630 errout_free: 2631 kfree_skb(skb); 2632 goto errout; 2633 } 2634 2635 void ip_rt_multicast_event(struct in_device *in_dev) 2636 { 2637 rt_cache_flush(dev_net(in_dev->dev)); 2638 } 2639 2640 #ifdef CONFIG_SYSCTL 2641 static int ip_rt_gc_interval __read_mostly = 60 * HZ; 2642 static int ip_rt_gc_min_interval __read_mostly = HZ / 2; 2643 static int ip_rt_gc_elasticity __read_mostly = 8; 2644 2645 static int ipv4_sysctl_rtcache_flush(struct ctl_table *__ctl, int write, 2646 void __user *buffer, 2647 size_t *lenp, loff_t *ppos) 2648 { 2649 struct net *net = (struct net *)__ctl->extra1; 2650 2651 if (write) { 2652 rt_cache_flush(net); 2653 fnhe_genid_bump(net); 2654 return 0; 2655 } 2656 2657 return -EINVAL; 2658 } 2659 2660 static struct ctl_table ipv4_route_table[] = { 2661 { 2662 .procname = "gc_thresh", 2663 .data = &ipv4_dst_ops.gc_thresh, 2664 .maxlen = sizeof(int), 2665 .mode = 0644, 2666 .proc_handler = proc_dointvec, 2667 }, 2668 { 2669 .procname = "max_size", 2670 .data = &ip_rt_max_size, 2671 .maxlen = sizeof(int), 2672 .mode = 0644, 2673 .proc_handler = proc_dointvec, 2674 }, 2675 { 2676 /* Deprecated. Use gc_min_interval_ms */ 2677 2678 .procname = "gc_min_interval", 2679 .data = &ip_rt_gc_min_interval, 2680 .maxlen = sizeof(int), 2681 .mode = 0644, 2682 .proc_handler = proc_dointvec_jiffies, 2683 }, 2684 { 2685 .procname = "gc_min_interval_ms", 2686 .data = &ip_rt_gc_min_interval, 2687 .maxlen = sizeof(int), 2688 .mode = 0644, 2689 .proc_handler = proc_dointvec_ms_jiffies, 2690 }, 2691 { 2692 .procname = "gc_timeout", 2693 .data = &ip_rt_gc_timeout, 2694 .maxlen = sizeof(int), 2695 .mode = 0644, 2696 .proc_handler = proc_dointvec_jiffies, 2697 }, 2698 { 2699 .procname = "gc_interval", 2700 .data = &ip_rt_gc_interval, 2701 .maxlen = sizeof(int), 2702 .mode = 0644, 2703 .proc_handler = proc_dointvec_jiffies, 2704 }, 2705 { 2706 .procname = "redirect_load", 2707 .data = &ip_rt_redirect_load, 2708 .maxlen = sizeof(int), 2709 .mode = 0644, 2710 .proc_handler = proc_dointvec, 2711 }, 2712 { 2713 .procname = "redirect_number", 2714 .data = &ip_rt_redirect_number, 2715 .maxlen = sizeof(int), 2716 .mode = 0644, 2717 .proc_handler = proc_dointvec, 2718 }, 2719 { 2720 .procname = "redirect_silence", 2721 .data = &ip_rt_redirect_silence, 2722 .maxlen = sizeof(int), 2723 .mode = 0644, 2724 .proc_handler = proc_dointvec, 2725 }, 2726 { 2727 .procname = "error_cost", 2728 .data = &ip_rt_error_cost, 2729 .maxlen = sizeof(int), 2730 .mode = 0644, 2731 .proc_handler = proc_dointvec, 2732 }, 2733 { 2734 .procname = "error_burst", 2735 .data = &ip_rt_error_burst, 2736 .maxlen = sizeof(int), 2737 .mode = 0644, 2738 .proc_handler = proc_dointvec, 2739 }, 2740 { 2741 .procname = "gc_elasticity", 2742 .data = &ip_rt_gc_elasticity, 2743 .maxlen = sizeof(int), 2744 .mode = 0644, 2745 .proc_handler = proc_dointvec, 2746 }, 2747 { 2748 .procname = "mtu_expires", 2749 .data = &ip_rt_mtu_expires, 2750 .maxlen = sizeof(int), 2751 .mode = 0644, 2752 .proc_handler = proc_dointvec_jiffies, 2753 }, 2754 { 2755 .procname = "min_pmtu", 2756 .data = &ip_rt_min_pmtu, 2757 .maxlen = sizeof(int), 2758 .mode = 0644, 2759 .proc_handler = proc_dointvec, 2760 }, 2761 { 2762 .procname = "min_adv_mss", 2763 .data = &ip_rt_min_advmss, 2764 .maxlen = sizeof(int), 2765 .mode = 0644, 2766 .proc_handler = proc_dointvec, 2767 }, 2768 { } 2769 }; 2770 2771 static struct ctl_table ipv4_route_flush_table[] = { 2772 { 2773 .procname = "flush", 2774 .maxlen = sizeof(int), 2775 .mode = 0200, 2776 .proc_handler = ipv4_sysctl_rtcache_flush, 2777 }, 2778 { }, 2779 }; 2780 2781 static __net_init int sysctl_route_net_init(struct net *net) 2782 { 2783 struct ctl_table *tbl; 2784 2785 tbl = ipv4_route_flush_table; 2786 if (!net_eq(net, &init_net)) { 2787 tbl = kmemdup(tbl, sizeof(ipv4_route_flush_table), GFP_KERNEL); 2788 if (!tbl) 2789 goto err_dup; 2790 2791 /* Don't export sysctls to unprivileged users */ 2792 if (net->user_ns != &init_user_ns) 2793 tbl[0].procname = NULL; 2794 } 2795 tbl[0].extra1 = net; 2796 2797 net->ipv4.route_hdr = register_net_sysctl(net, "net/ipv4/route", tbl); 2798 if (!net->ipv4.route_hdr) 2799 goto err_reg; 2800 return 0; 2801 2802 err_reg: 2803 if (tbl != ipv4_route_flush_table) 2804 kfree(tbl); 2805 err_dup: 2806 return -ENOMEM; 2807 } 2808 2809 static __net_exit void sysctl_route_net_exit(struct net *net) 2810 { 2811 struct ctl_table *tbl; 2812 2813 tbl = net->ipv4.route_hdr->ctl_table_arg; 2814 unregister_net_sysctl_table(net->ipv4.route_hdr); 2815 BUG_ON(tbl == ipv4_route_flush_table); 2816 kfree(tbl); 2817 } 2818 2819 static __net_initdata struct pernet_operations sysctl_route_ops = { 2820 .init = sysctl_route_net_init, 2821 .exit = sysctl_route_net_exit, 2822 }; 2823 #endif 2824 2825 static __net_init int rt_genid_init(struct net *net) 2826 { 2827 atomic_set(&net->ipv4.rt_genid, 0); 2828 atomic_set(&net->fnhe_genid, 0); 2829 get_random_bytes(&net->ipv4.dev_addr_genid, 2830 sizeof(net->ipv4.dev_addr_genid)); 2831 return 0; 2832 } 2833 2834 static __net_initdata struct pernet_operations rt_genid_ops = { 2835 .init = rt_genid_init, 2836 }; 2837 2838 static int __net_init ipv4_inetpeer_init(struct net *net) 2839 { 2840 struct inet_peer_base *bp = kmalloc(sizeof(*bp), GFP_KERNEL); 2841 2842 if (!bp) 2843 return -ENOMEM; 2844 inet_peer_base_init(bp); 2845 net->ipv4.peers = bp; 2846 return 0; 2847 } 2848 2849 static void __net_exit ipv4_inetpeer_exit(struct net *net) 2850 { 2851 struct inet_peer_base *bp = net->ipv4.peers; 2852 2853 net->ipv4.peers = NULL; 2854 inetpeer_invalidate_tree(bp); 2855 kfree(bp); 2856 } 2857 2858 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = { 2859 .init = ipv4_inetpeer_init, 2860 .exit = ipv4_inetpeer_exit, 2861 }; 2862 2863 #ifdef CONFIG_IP_ROUTE_CLASSID 2864 struct ip_rt_acct __percpu *ip_rt_acct __read_mostly; 2865 #endif /* CONFIG_IP_ROUTE_CLASSID */ 2866 2867 int __init ip_rt_init(void) 2868 { 2869 int rc = 0; 2870 int cpu; 2871 2872 ip_idents = kmalloc(IP_IDENTS_SZ * sizeof(*ip_idents), GFP_KERNEL); 2873 if (!ip_idents) 2874 panic("IP: failed to allocate ip_idents\n"); 2875 2876 prandom_bytes(ip_idents, IP_IDENTS_SZ * sizeof(*ip_idents)); 2877 2878 ip_tstamps = kcalloc(IP_IDENTS_SZ, sizeof(*ip_tstamps), GFP_KERNEL); 2879 if (!ip_tstamps) 2880 panic("IP: failed to allocate ip_tstamps\n"); 2881 2882 for_each_possible_cpu(cpu) { 2883 struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu); 2884 2885 INIT_LIST_HEAD(&ul->head); 2886 spin_lock_init(&ul->lock); 2887 } 2888 #ifdef CONFIG_IP_ROUTE_CLASSID 2889 ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct), __alignof__(struct ip_rt_acct)); 2890 if (!ip_rt_acct) 2891 panic("IP: failed to allocate ip_rt_acct\n"); 2892 #endif 2893 2894 ipv4_dst_ops.kmem_cachep = 2895 kmem_cache_create("ip_dst_cache", sizeof(struct rtable), 0, 2896 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 2897 2898 ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep; 2899 2900 if (dst_entries_init(&ipv4_dst_ops) < 0) 2901 panic("IP: failed to allocate ipv4_dst_ops counter\n"); 2902 2903 if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0) 2904 panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n"); 2905 2906 ipv4_dst_ops.gc_thresh = ~0; 2907 ip_rt_max_size = INT_MAX; 2908 2909 devinet_init(); 2910 ip_fib_init(); 2911 2912 if (ip_rt_proc_init()) 2913 pr_err("Unable to create route proc files\n"); 2914 #ifdef CONFIG_XFRM 2915 xfrm_init(); 2916 xfrm4_init(); 2917 #endif 2918 rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL); 2919 2920 #ifdef CONFIG_SYSCTL 2921 register_pernet_subsys(&sysctl_route_ops); 2922 #endif 2923 register_pernet_subsys(&rt_genid_ops); 2924 register_pernet_subsys(&ipv4_inetpeer_ops); 2925 return rc; 2926 } 2927 2928 #ifdef CONFIG_SYSCTL 2929 /* 2930 * We really need to sanitize the damn ipv4 init order, then all 2931 * this nonsense will go away. 2932 */ 2933 void __init ip_static_sysctl_init(void) 2934 { 2935 register_net_sysctl(&init_net, "net/ipv4/route", ipv4_route_table); 2936 } 2937 #endif 2938